1. Field of the Invention
The present invention relates to the technical fields of an inner panel and a loudspeaker apparatus.
2. Description of the Related Art
In a conventional in-vehicle loudspeaker apparatus, a Helmholtz resonator is arranged so as to suppress an in-vehicle inner panel from being vibrated, and attenuates generated vibration to prevent an unnecessary sound from being produced (for example, see Japanese Patent Application Laid-Open No. 09-37371).
However, in the conventional technique described above, a plurality of Helmholtz resonators must be arranged to absorb sound waves having different frequencies. For this reason, parts increase in number, so that the manufacturing cost disadvantageously increases.